Better Ebola Vaccine For Monkeys Offers Hope for Humans

Published: August 8, 2003

Federal scientists have developed a fast-acting, single-shot vaccine that makes monkeys immune to the Ebola virus six times as fast as an earlier version.

If the same approach works in humans, it could control or prevent outbreaks of the rare infection that causes high fever, severe pain, bleeding from the eyes and usually death within a few days.

Scientists not connected with the experiment said that if the vaccine worked in other primates, it would probably work in humans. Health workers in Africa -- the only place the few outbreaks have occurred -- might be the most likely recipients of an approved Ebola vaccine.

The experimental vaccine has not been tested on humans. But a developer, Dr. Gary J. Nabel of the National Institutes of Health, said he hoped to have it ready for human studies by the end of next year, pending approval by the Food and Drug Administration. Dr. Nabel also developed a version of the vaccine for monkeys three years ago, but the injections were administered over a six-month period that included a booster shot.

Dr. C. J. Peters, a microbiologist at the University of Texas Medical Branch in Galveston, said more animal trials were needed before regulatory approval of a human vaccine could be sought. He said it would also be important to determine how the vaccine conveys its immunity and how long it works.

Researchers tested the vaccine by giving eight macaque monkeys a single injection of a weakened virus modified with a protein from the Ebola virus. Twenty-eight days later, the monkeys were injected with an Ebola virus strain taken from a human who died from the disease in 1995. All eight monkeys remained healthy. All the monkeys in a separate control group that were not given the vaccine died after they were exposed to the virus.